TIV uptake low despite good effectiveness in young children
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The trivalent influenza vaccine appeared safe and effective in a study of Australian children younger than 2 years. However, vaccine uptake remains low, according to recent study results published in Pediatrics.
Christopher C. Blyth, MBBS, of the School of Paediatrics and Child Health at the University of Western Australia and Princess Margaret Hospital, and colleagues evaluated 2,001 children aged 6 to 59 months (median age, 1.9 years) between 2008 and 2012 to determine the effectiveness of the trivalent influenza vaccine (TIV). Researchers used a test-negative design with two control groups: influenza test-negative patients and other-virus-detected (OVD) patients.
No participants had a pre-existing condition associated with severe influenza; however, 11.8% of participants had a comorbid condition, most commonly chronic asthma, other chronic respiratory disease, chronic neurologic disease and heart disease.
Twenty percent of participants had influenza, most commonly influenza A (14.1%), compared with 6.3% for influenza B. Nearly 60% of participants had another respiratory virus detected most. Human picornaviruses (n=673) was the most common noninfluenza virus detected, followed by respiratory syncytial virus A/B (n=312); human parainfluenza virus types 1 to 4 (n=193); adenoviruses B through D (n=157); bocaviruses (n=126); and coronaviruses OC43/229E (n=61).
Overall, 24% of participants received a vaccine with 15.5% being fully vaccinated and 8.5% being partially vaccinated. During the 2008-2009 influenza season, vaccine uptake was 55.1% compared with 9.7% during the 2011-2012 season (P<.001). Thirty percent of participants received a vaccine compared with 23.8% of participants without a comorbidity (P=.045).
In 2009, 75 participants had influenza detected leading to these participant being excluded from the vaccine effectiveness portion of the study leaving 1,514 participants.
Overall, vaccine effectiveness was 64.7% in test-negative participants and 65.8% among OVD participants.
Among test-negative participants, vaccine effectiveness was great toward influenza A (79.6%) compared with influenza B (47.8%).
“Our findings reveal the effectiveness of TIV in healthy young children, including those younger than 2 years of age and support the current ACIP recommendations for young children,” the researchers wrote. “Consistent results were shown by using two different control groups. The inclusion of influenza vaccine in routine childhood immunization schedules will result in increased vaccine uptake. Ensuring access to a safe TIV is paramount to the successful implementation of a pediatric influenza vaccination program.”
Disclosure: See the study for a full list of disclosures.